Method for coding mailing items

ABSTRACT

A method for coding mailing items, in which a determination of the surface available for applying an unambiguous code to arriving mailing items is conducted and an application of the unambiguous code with a number of code signs that is adapted to the respectively determined surface available for coding is performed.

BACKGROUND OF THE INVENTION

The invention relates to a method for coding mailing items by means ofapplied, readable code signs. Information is nowadays applied by machineto mailing items during the automatic processing. This can occur byprinting on a barcode (or other code) or by printing on clear text.

The printed-on information can:

Contain target information, meaning information on the recipient of themail item, which is used, for example, for sorting;

Contain an identification of the mail item, so that a later recognitionis possible. Such an identification is frequently called anidentification code (ID code) and is necessary, for example, for theoffline processing;

Contain information on the sender;

Contain statistical and other information.

Combinations of two or more of the aforementioned types of informationare also standard. Frequently, additional, redundant information isapplied to reduce the risk of reading errors. At the same time, theprinting technique and the reading technique must be as simple andinexpensive as possible, while the reading safety must be as high aspossible. At the present time, the method that is easiest to use and atthe same time relatively secure when using bar codes is the single-spaceprinting of a fluorescent bar/no-bar code with a bar spacing of, forexample, 1.5 mm.

The coding as well as the number of coded signs and the spacing betweencoded signs have until now been determined in that the codes,particularly the identification codes, for the most frequent mailingitems with higher standard size are unambiguous and, if possible, fillthe space provided for it.

If the mailing items also include items with a length shorter than thestandard length, it can happen that the available space for the ID codemay no longer be sufficient when maintaining the agreed-upon spacingbetween code signs. However reducing the size of the code signs and thespacing would result in higher reading and printing expenses as well asa reduction in the reading safety.

It is therefore the object of the invention specified in claim 1 toclearly code mailing items of varied size by maintaining the size andspacing between the coded signs selected for large mailing items.

It is possible to maintain the original size and the spacing betweencode signs despite the fact that the mailing items are smaller bymeasuring the area available for applying the code on the arrivingmailing items, as well as by selecting and subsequently applying anunambiguous code with a code sign number that is adapted to therespectively determined surface for coding.

Several different methods can be used to determine the dimensionsavailable for coding. Thus, the area not printed on and its dimensionsare determined during the optical scanning of the surface of the mailingitem at the agreed-upon location. In many cases, it is sufficient todetermine or simply measure the length of the mailing item and reduce itby a fixed amount.

It is advantageous to reduce the existing redundant information in orderto reduce the number of digits for an ID code. With smaller and inparticular shorter items, which therefore have a reduced number of codesigns, it is possible to check whether the ID code is unambiguous bykeeping a statistic on the frequency of different lengths for itemsprocessed so far, which are available for the ID code and effect thenumber of signs to be applied. The unambiguous condition exists if forthe observed time interval all accumulated mailing items with the IDcode number adapted to the length can be clearly distinguished.

The invention is explained in the following with the aid of a drawingand exemplary embodiments.

DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a flow chart for the steps of the invention.

DETAILED DESCRIPTION OF THE INVENTION EXAMPLE 1 FOR SHORTENING THE IDCODE

A 10-digit decimal number is to be printed on in clear text asunambiguous code sign for the mailing item, so that daily 100 millionitems can be distinguished unambiguously over a period of 100 days.Based on statistical surveys, it is known that 3% of the items are tooshort to accommodate 10 digits, but are long enough to have 9 digitsprinted on. The supply of 10¹⁰ code sign sequences that can bedifferentiated contains not only 10-digit numbers, but also shorterones, namely

10⁹nine-digit

+10⁸eight-digit

+. . .

code sequences (a leading zero does not have to be printed in thedecimal system).

Based on this, up to 11.1% of the items can be provided with codes thatare shorter than the 10-digit code signs. This share is higher than 3%,meaning all items that appear can be coded unambiguously, without losingunambiguousness and without other disadvantages.

EXAMPLE 2 FOR SHORTENING ID CODES

The information to be printed is to be printed in the bar/no-bartechnique and is to consist of 40 bits of target information and 40 bitsof ID code. With the understanding that a printed bar means a binary“one” and an omitted bar a binary “zero,” the available store of 2⁴⁰code sign sequences contains:

2³⁹ sequences with a length of 39 bars,

2³⁸ sequences with a length of 38 bars, etc.

If only 75 instead of 80 bars can be applied to short items, forexample, more than 3% of the code sign sequences (2³⁵/2⁴⁰=0.031) arestill available for these cases.

EXAMPLE 3 FOR SHORTENING OPTIONAL CODES PROVIDED WITH REDUNDANCY

In order to reduce errors, redundancy codes are added to the informationto be printed. Three optional methods are available for this. The totalnumber of printable code sign sequences thus is composed of threepartial segments of code sign sequences of varied length. Depending onthe length of the measured mailing item, a code sign sequence isselected from the partial segment that can just barely be printed on theavailable space.

EXAMPLE 4 FOR SHORTENING WITH THE AID OF DIFFERENT TYPES OF CODING

Normally, the code to be applied must represent an information presentas decimal number. It is favorable if the code can be deciphered easilyby humans with the aid of a small template. When using the bar-no-bartechnique, it suggests itself to use a group of four bars for eachposition of the decimal number, which is then easily decipherable with a10-line table. If the 4-state bar technique is used, each decimal placecan be represented by two bars. A 3-digit decimal number requirestherefore 3*4=12 bars in the bar-no-bar technique or 3*2=6 bars in the4-state technique. The number of bars and thus the required printinglength on the mailing item can be reduced by changing to a binary codingat the cost of easy decipherability for humans. For the binaryrepresentation, it is sufficient to have 10 bars in the bar-no-bartechnique or 5 bars in the 4-state bar technique to show each 3-digitdecimal number because 2¹⁰>1000 and 4⁵>1000. The same applies if text iscoded in place of decimal numbers. As illustrated in FIG. 1, initially,a determination of the surface available for applying the unambiguouscode to the arriving mailing items is made 1. A statistic is kept on thefrequency of varied the lengths of available codes dependent from the IDcodes of mailing items processed until now during a fixed time period 4.Following this, it is determined whether the free surface issufficiently large for the normal, standard number of characters, giventhe standard character size 2. If this is the case, a corresponding codeis printed on 3. If the surface is too small, the code length is adaptedto fit the determined print area 5, by taking into consideration thenumber of mail items that must be differentiated according to thestatistic determined in step 4. Subsequently, this coding is printed onthe mail item 6.

What is claimed is:
 1. A method for coding mailing items, comprising thefollowing steps: a) determining the surface area available for applyingan unambiguous code to arriving mailing items; and b) applying theunambiguous code with a number of code signs, the number being adaptedto the respectively determined surface area available for applying thecoding.
 2. A method according to claim 1, further comprising the stepsof: adapting a number of redundancy signs contained in the code to therespectively determined surface available for coding.
 3. A methodaccording to claim 1, further comprising the steps of: testing theunambiguousness of a selected identification code (ID code); storing astatistic on the frequency of varied lengths of the remaining availablecodes dependent on the ID codes of mailing items processed during afixed time period, which affects the number of code signs in the ID codeto be applied; determining whether all the mailing items that haveaccumulated during the fixed time period with an ID code can bedistinguished clearly.